Sensory evaluation of Belgian and U.S. red/brown sour beers

Technical Session 08: Sensory Session
Jeff E Clawson, Oregon State University, Corvallis, Oregon, USA
Co-author(s): Victor Algazzali, Yanping Qian, Michael Qian, and Thomas Shellhammer, Oregon State University, Corvallis, OR, USA

ABSTRACT: Sour ales from the Northern region of Belgium are unique in their sensorial aspects, with varying degrees of sourness and aromatic qualities. These “Flemish” red or brown ales are traditionally aged in oak barrels for up to 2 years, although some are aged in stainless steel. Some are blended with younger beer before packaging. Sour beers brewed in a similar style are being produced by some U.S. craft brewers. To date, there has been little research comparing and contrasting the Belgian beers with those produced in the United States. This research focused on examining this style of beer from the two respective countries using instrumental and sensory approaches. Six commercial sour beers from the Flanders region of Belgium were chosen based on their popularity and availability, while seven U.S. beers were chosen based on their similarity to the Flemish sour beer style with regards to aging, color, and sour character. Instrumental analyses included measures of acidity (pH, TA, and organic acid profiles), volatile aromas (ethyl and lactate esters), and markers of Brettanomyces activity (4-ethylphenol and 4-ethylguiacol). Descriptive sensory analysis was performed using a panel of 13 trained beer tasters and a ballot of 22 attributes. The U.S. beers were significantly higher and more variable in OG, ABV, and acidity than their Belgian counterparts but were similar in visual appearance and color. The U.S. beers were perceived as being more bitter, salty, sour, and astringent, with greater Brettanomyces character than the Belgian beers, while the Belgian beers tended to be sweeter and possessed greater coca/coffee notes. There was less differentiation between the two countries for descriptive terms such as dark fruit, cherry, fruity, caramel, tobacco/black tea, and sweaty/cheesey. Instrumental results of esters and Brettanomyces markers mirrored these similarities. These results reveal that sour beers originating from the United States and Belgium have many similarities, while at the same time expressing their own uniqueness.

Jeff Clawson received both his M.S. and B.S. degrees from Oregon State University in Corvallis, OR. In 1993 he began employment with the Food Science and Technology Department at OSU as a faculty research assistant working with Mina McDaniel. He conducted both descriptive and commercial sensory panels involving beer and food products. Since 2001 he has been professional faculty, managing both the food processing plant and research brewery, supporting the research program of Thomas Shellhammer. He has been an active member at the local level of the Institute of Food Technologists, ASBC, and MBAA.